This Bearing Life spreadsheet from 3D-LABS follows ISO standards and gives instant, checkable results for practising engineers — no manual derivation required.
This Excel spreadsheet calculates rolling bearing L10 life (the life at which 10% of a bearing population is expected to fail) per ISO 281:2007 and SKF General Catalogue 6000 EN, using the modified rating life equation Lnm = a1 × aISO × (C/P)^p. It is the standard calculation required for pump, gearbox, compressor, and conveyor bearing specification.
What standard does this calculation follow?
ISO 281:2007 (Rolling bearings — Dynamic load ratings and rating life), ISO/TR 1281-2:2008 (explanatory notes), SKF General Catalogue 6000 EN, and ABMA Standard 9 (load ratings for ball bearings) and ABMA Standard 11 (roller bearings).
What formula is used?
Modified rating life: Lnm = a1 × aISO × (C/P)^p (hours), where C = basic dynamic load rating (kN), P = equivalent dynamic bearing load (kN), p = 3 for ball bearings / 10/3 for roller bearings, a1 = reliability factor (a1 = 1.0 for L10), aISO = life modification factor per ISO 281 Annex A (viscosity ratio κ and contamination factor eC).
Frequently Asked Questions
What is the ISO 281 L10 bearing life formula?
L10 = (C/P)^p × 10^6 revolutions, where C = basic dynamic load rating (kN), P = equivalent dynamic load (kN), p = 3 for ball bearings, p = 10/3 for roller bearings. For modified L10m life including lubrication and contamination: Lnm = a1 × aISO × L10 per ISO 281:2007.
What is the difference between L10 and L10h bearing life?
L10 is expressed in millions of revolutions. L10h is in operating hours: L10h = (10^6 / 60n) × L10, where n = speed in rpm. For a bearing running at 1,500 rpm with L10 = 50 million revolutions: L10h = (10^6 / 90,000) × 50 = 555 hours.
What inputs are needed for SKF bearing life calculation?
Required: radial load Fr (kN), axial load Fa (kN), bearing type (deep groove ball, CARB, tapered roller, etc.), bearing designation (e.g., SKF 6312), operating speed (rpm), lubricant viscosity at operating temperature (cSt), and cleanliness class per ISO 4406.
What’s Included
An instant Excel download with the complete formula set, a worked numerical example, and reference to the governing standard — ready to adapt to your own project inputs.
